Flame-retardant resin composition

Abstract: A flame-retardant resin composition obtainable by melt-kneading 100 parts by weight of (A) a thermoplastic resin and 5-100 parts by weight of a melt reaction product between (B) at least one epoxy-modified resin and (C) at least one halogen-free flame-retardant compound, said at least one epoxy-modified resin (B) being selected from the group consisting of an epoxy-modified polyolefin resin having epoxy groups in the molecule, an epoxide of a hydrogenated block copolymer obtained by hydrogenating a block copolymer comprising at least one polymer block composed mainly of a vinyl aromatic compound and at least one polymer block composed mainly of a conjugated diene compound, an epoxide of a terblock copolymer comprising a polymer block composed mainly of an acrylic resin, at least one polymer block composed mainly of a conjugated diene compound and at least one polymer block composed mainly of a vinyl aromatic compound, and an epoxide of an acrylic resin, said at least one halogen-free flame-retardant compound (C) being selected from the group consisting of a phenolic resin and phosphorus-, nitrogen- and boron-containing compounds having epoxy-reactive functional groups.

Description: The present invention relates to a flame-retardant resin composition superior in low-temperature resistance and flame retardancy, suitably used in various molded articles obtained by injection molding, extrusion, etc. In general, thermoplastic resins are superior in mechanical properties, heat resistance, electrical properties, moldability, etc. and are in wide use in general industries as electrical device or apparatus parts, automobile parts, precision machine parts, etc. These thermoplastic resins, however, have a drawback of being burnt relatively easily and find limited applications in usages wherein flame retardancy is required, such as electronic and electrical parts (e.g. TV parts), parts used in automobile engine room, and the like. It is therefore required strongly to impart excellent flame retardancy to thermoplastic resins. Hence, there were made a number of proposals of adding various halogen compounds and phosphorus compounds. These proposals are not satisfactory, because the addition of said flame retardants imparts excellent flame retardancy but reduces the excellent mechanical properties, electrical properties and processability inherently possessed by thermoplastic resins. The present invention is intended to provide a flame-retardant resin composition of improved flame retardancy using a halogen-free flame-retardant compound, without inviting reduction in inherent properties of thermoplastic resins. The present inventors made a study on combinations of a thermoplastic resin and a halogen-free flame-retardant compound. As a result, it was found that simple mixing of a thermoplastic resin and a phenolic resin can give improvement in flame retardancy but invites reduction in properties such as low-temperature resistance, heat resistance and the like. It was also found that simple mixing of a thermoplastic resin and a phosphorus-, nitrogen- or boron-containing compound gives insufficient improvement in flame retardancy and further invites bleeding and reduction in properties such as low-temperature resistance, heat resistance and the like. The present inventors made a further study. As a result, it was found that a melt reaction product between an epoxy-modified resin [component (B) of the present invention] and a halogen-free flame-retardant compound [component (C) of the present invention] can cover the fragility of a phenolic resin, can improve the bleeding of a phosphorus-, nitrogen- or boron-containing compound, and can alleviate the drawbacks of the prior art such as insufficient low-temperature resistance, mechanical properties and the like. The finding has led to the completion of the present invention. The present invention relates to a flame-retardant resin composition obtained by melt-reacting 100 parts by weight of (A) a thermoplastic resin and 5-100 parts by weight of a melt reaction product between (B) an epoxy-modified resin and (C) a halogen-free flame-retardant compound. Preferably, the present invention relates to a flame-retardant resin composition obtained by melt-kneading 100 parts by weight of (A) a thermoplastic resin, 5-100 parts by weight of a melt reaction product among (B) an epoxy-modified resin, (C) a halogen-free flame-retardant compound, and 0.01-5% by weight, based on the total of (B) and (C), of (E) a catalyst capable of promoting the reaction between (B) and (C), and 3-160 parts by weight of (D) an inorganic hydrate. The thermoplastic resin used as the component (A) of the present invention is not particularly restricted and may be a commercial product. It is preferably a polyolefin resin, a polystyrene resin or a polyphenylene ether resin. The polyolefin resin is not particularly restricted and may be a commercial product. The polyolefin resin is preferably a polyethylene resin or a polypropylene resin. Also, a modified polyethylene resin can be used in the present invention. The modified polyethylene resin is not particularly restricted and may be a commercial product. It is exemplified by an ethylene-(meth)acrylic acid copolymer and an ethylene-(meth)acrylic acid ester copolymer [e.g. ethylene-methyl (meth)acrylate copolymer or ethylene-ethyl (meth)acrylate copolymer]. Also, a modified polypropylene resin can be used in the present invention. The modified polypropylene resin is not particularly restricted and may be a commercial product. It is exemplified by an ethylene-propylene copolymer and an ethylene-propylene-diene copolymer. These resins can be used singly or in combination of two or more. The polystyrene resin is not particularly restricted and may be a commercial product. It is exemplified by homopolymers of styrene or a styrene derivative [e.g. α-substituted styrene (e.g. α-methylstyrene) or vinyltoluene] and copolymers of said monomer as a main component with at least one monomer copolymerizable therewith, such as acrylonitrile, butadiene or isoprene. The polyphenylene ether resin is not particularly restricted and may be a commercial product. It is exemplified by a poly(2,6-dimethylphenylene-1,4-ether) resin, a poly(2,6-diethylphenylene-1,4-ether) resin, a poly(2-methyl-6-ethylphenylene-1,4-ether) resin and styrene-modified polyphenylene ether resins wherein the proportion of styrene is various. The epoxy-modified resin, which is the component (B) of the present invention, has a function of suppressing the reduction in the low-temperature resistance and mechanical properties which arises when a thermoplastic resin is mixed with a phenolic resin, which has a relatively low molecular weight and is fragile, and also has a function of suppressing the bleeding and reduction in low-temperature resistance and heat resistance which arise when said thermoplastic resin is mixed with a phosphorus-, nitrogen- or boron-containing compound. Thus, the epoxy-modified resin is a very important component. That is, the epoxy-modified resin (B) is at least one resin selected from the group consisting of an epoxy-modified polyolefin resin having epoxy groups in the molecule, an epoxide of a hydrogenated block copolymer obtained by hydrogenating a block copolymer comprising at least one polymer block composed mainly of a vinyl aromatic compound and at least one polymer block composed mainly of a conjugated diene compound, an epoxide of a terblock copolymer comprising a polymer block composed mainly of an acrylic resin, at least one polymer block composed mainly of a conjugated diene compound and at least one polymer block composed mainly of a vinyl aromatic compound, and an epoxide of an acrylic resin. The epoxy-modified polyolefin having epoxy groups in the molecule, used in the present invention is not particularly restricted and may be a commercial product. It is exemplified by an ethylene-glycidyl methacrylate copolymer, a terpolymer between an ethylene-acrylic acid copolymer, an ethylene-methacrylic acid copolymer, an ethylene-acrylate copolymer or an ethylene-methacrylate copolymer and glycidyl methacrylate, and a polypropylene grafted with glycidyl methacrylate. The epoxy-modified hydrogenated block copolymer having epoxy groups, used in the present invention is not particularly restricted and may be a commercial product. It is exemplified by an epoxidized styrene-ethylene/butylene-styrene block copolymer and an epoxidized styrene-ethylene/propylene-styrene block copolymer. The epoxy-modified block copolymer used in the present invention can be obtained by adding an epoxy compound having an unsaturated double bond, to a hydrogenated block copolymer to give rise to an addition reaction. The epoxide of a terblock copolymer comprising a polymer block composed mainly of an acrylic resin, at least one polymer block composed mainly of a conjugated diene compound and at least one polymer block composed mainly of a vinyl aromatic compound and the epoxide of an acrylic resin, both used in the present invention, are not particularly restricted and may be commercial products. They are exemplified by an epoxidized methacrylate-butadiene-styrene copolymer and an epoxidized methyl acrylate resin, respectively. The phenolic resin used as the component (C) of the present invention is not particularly restricted and may be a commercial product. It can be obtained, for example, by feeding a phenol and formalin into a reactor at a formaldehyde/phenol ratio of 0.5-1.0, adding thereto a catalyst (e.g. oxalic acid, hydrochloric acid, sulfuric acid or toluenesulfonic acid), heating and refluxing the mixture for an appropriate period of time to give rise to a reaction, dehydrating the reaction mixture under vacuum or by allowing the mixture to stand, to remove the separated water, and removing residual water and unreacted phenol. The thus obtained resins and the phenolic resins obtained by co-condensation using a plurality of starting materials are used singly or in combination of two or more. The phosphorus-, nitrogen- or boron-containing compound having epoxy-reactive functional group, used as the component (C) of the present invention is not particularly restricted and may be a commercial product. The functional group is preferably hydroxyl group, carboxyl group, acid anhydride group, or amino group. The compound is exemplified by phosphorus-containing compounds such as polyphosphoric acid, polyammonium phosphate, amino-, hydroxyl- or carboxyl-containing phosphoric acid esters; boron-containing compounds such as boric acid or zinc borate; melamine and melamine derivatives such as melamine cyanurate, melamine-phosphoric acid salt or melamine borate; and guanidine and guanidine derivatives such as sulfamic acid-guanidine salt or phosphoric acid-guanidine salt. The inorganic hydrate used as the component (D) of the present invention is used for giving higher flame retardancy. It is not particularly restricted and may be a commercial product. It is exemplified by magnesium hydroxide, aluminum hydroxide and calcium hydroxide. The catalyst used as the component (E) of the present invention, capable of promoting the reaction between the epoxy-modified resin (B) and the halogen-free flame-retardant compound (C) is not particularly restricted and may be a commercial product. It is exemplified by imidazoles such as dimethylimidazole ; amines and their derivatives such as diazabicycloundecene or dimethylbenzylamine; and organic phosphines and their derivatives such as triphenylphosphine. The flame-retardant resin composition of the present invention can be obtained by (1) feeding a thermoplastic resin [the component (A)], an epoxy-modified resin [the component (B)] and a halogen-free flame-retardant compound [the component (C)] into a kneader under pressure or a Banbury mixer at one time and melt-kneading them at 150-300°C for 10-30 minutes, or (2) melt-kneading an epoxy-modified resin [the component (B)], a halogen-free flame-retardant compound [the compound (C)] and, if necessary, a catalyst [the component (E)] at 100-300°C for 10-30 minutes, then adding a thermoplastic resin [the component (A)] and other additives and melt-kneading the mixture. The latter method is preferable because it allows for selective mixing of the epoxy-modified resin [the component (B)] and the halogen-free flame-retardant compound [the component (C)]. In the flame-retardant resin composition of the present invention, 100 parts by weight of the thermoplastic resin (A) must be mixed with 5-100 parts by weight of the melt reaction product between the epoxy-modified resin (B) and the halogen-free flame-retardant compound (C). When the amount of the melt reaction product between the epoxy-modified resin (B) and the halogen-free flame-retardant compound (C) is less than 5 parts by weight, the resulting flame-retardant resin composition has insufficient flame retardancy. When the amount is more than 100 parts by weight, the properties of the thermoplastic resin are reduced in the resulting flame-retardant resin composition. When the amount of the catalyst (E) capable of promoting the reaction between the epoxy-modified resin (B) and the halogen-free flame-retardant compound (C) is less than 0.01% by weight based on the total of (B) and (C), the effect of promoting said reaction is insufficient. When the amount is more than 5% by weight, said effect does not show substantial increase any more. The flame-retardant resin composition of the present invention has high flame retardancy without substantially reducing the properties of the thermoplastic resin [the component(A)]. The reason is presumed to be that the reaction product between the epoxy-modified resin [the component (B)] and the halogen-free flame-retardant compound [the component (C)] has, in the molecule, a moiety compatible with the thermoplastic resin (A) and a moiety compatible with the halogen-free flame-retardant compound (C) and, as a result, the fine dispersion of the halogen-free flame-retardant compound (C) in the thermoplastic resin (A) becomes possible. The flame-retardant resin composition of the present invention can further contain, depending upon the application and purpose, other components such as inorganic filler (e.g. talc, mica, calcium carbonate or wollastonite), coupling agent, reinforcing agent (e.g. glass fiber or carbon fiber), flame-retardant assistant, antistatic agent, stabilizer, pigment, releasing agent, impact resistance improver (e.g elastomer). The flame-retardant resin composition of the present invention can be easily processed into molded articles by a method used in ordinary processing of thermoplastic resins, such as injection molding or extrusion. The present invention is hereinafter described specifically by way of Examples. Examples 1-8 and Comparative Examples 1-12 Flame-retardant resin compositions were prepared as follows. When a polyolefin resin or a polystyrene resin was used as the component (A), the polyolefin or polystyrene resin (A), an epoxy-modified resin (B), a halogen-free flame-retardant compound (C) and an inorganic hydrate (D) were fed at one time and were melt-kneaded using a kneader, at 190°C for 30 minutes. When a polyphenylene ether resin was used as the component (A), the polyphenylene ether resin (A), an epoxy-modified resin (B), a halogen-free flame-retardant compound (C) and an inorganic hydrate (D) were fed at one time and were melt-kneaded using a kneader, at 300°C for 30 minutes. Each of the resulting flame-retardant resin compositions was extruded into a sheet, and various test pieces were prepared from the sheet. Tensile test was conducted in accordance with ASTM D 638; heat-deformation temperature was measured in accordance with ASTM D 648 (4.6 kgf/cm 2 ); Izod impact test was conducted in accordance with JIS K 6871; low-temperature resistance was measured in accordance with JIS K 6301; oxygen index was measured in accordance with ASTM D 2863; and burning test was conducted in accordance with the safety standard UL 94 of Underwriters Laboratories and its evaluation was made according to the following yardstick. ○ : burning time = shorter than 10 seconds ▵ : burning time = 10 seconds or longer x : completely burnt The compounding recipe and evaluation results of each composition prepared above are shown in Tables 1-4. The components used in each composition are as follows. Component (A) Polyolefin resin PE: a polyethylene manufactured by Mitsui Petrochemical Industries, Ltd., Ultrazex 2022 L (trade name) EMMA: a methyl methacrylate-modified polyethylene manufactured by Sumitomo Chemical Co., Ltd., Acryft WH102 (trade name) PP: a polypropylene manufactured by Sumitomo Chemical Co., Ltd., Sumitomo Noblen H501 (trade name) Polystyrene resin PS: a polystyrene manufactured by Showa Denko K.K., Esbrite 500A (trade name) ABS: an ABS resin manufactured by Mitsubishi Rayon Co., Ltd., Diapet ABS RSE-7 (trade name) Polyphenylene ether resin PPE (1): a polyphenylene ether manufactured by ASAHI CHEMICAL INDUSTRY CO., LTD., Xyron X0061 (trade name) PPE (2): a polyphenylene ether manufactured by MITSUBISHI GAS CHEMICAL CO., INC., Iupiace AV40 (trade name) Component (B) EP-PO: an epoxy-modified polyolefin manufactured by Sumitomo Chemical Co., Ltd., Bond Fast 20M (trade name) EP-SEBS: an epoxy-modified styrene-ethylene/butylene-styrene block copolymer manufactured by ASAHI CHEMICAL INDUSTRY CO., LTD., Tuftec Z-514 (trade name) Component (C ) PN: a straight phenol novolac resin manufactured by Sumitomo Durez, Sumilite Resin PR-51470 (trade name) AA-1000: an amino group-containing phosphoric acid ester manufactured by Nippon Soda Co., Ltd. CR-757: a hydroxyl group-containing phosphoric acid ester manufactured by Daihachi Kagaku K.K. PX-201: a condensed phosphoric acid ester manufactured by Daihachi Kagaku K.K. MPP-A: phosphoric acid-melamine salt manufactured by Sanwa Chemical. Boric acid Component (D ) Mg(OH) 2 Al(OH) 3 Component (E ) TPP: triphenylphosphine (Polyolefin resins) Examples 1 2 3 4 Compounding (parts by weight) PE 100 100 PP 100 100 PN 21 16 25 9 EP-PO 9 25 EP-SEBS 24 Mg(OH) 2 100 100 Al(OH) 3 100 100 Properties Oxygen index 31.0 31.2 32.4 31.2 Low-temperature resistance (°C) -60 -56 -54 -59 Tensile strength (Kg/cm 2 ) 150 280 120 260 Tensile elongation (%) 530 520 480 510 UL94 First firing o o o o Second firing o o o o Melt drops None None None None (Polyolefin resins) Comparative Examples 1 2 3 4 5 6 Compounding (parts by weight) PE 100 100 100 PP 100 100 100 PN 40 90 2 EP-PO 40 20 EP-SEBS 2 Mg(OH) 2 100 100 100 Al(OH) 3 100 100 100 Properties Oxygen index 28.1 28.3 30.9 28.2 30.9 29.2 Low-temperature resistance (°C) -50 -59 -20 -48 -10 -28 Tensile strength (Kg/cm 2 ) 170 260 160 250 100 260 Tensile elongation (%) 670 650 320 550 220 520 UL94 First firing x x o x o x Second firing x x x x x x Melt drops Present Present none Present none Present (Polystyrene or polyphenylene ether resin) Examples 5 6 7 8 Compounding (parts by weight) PS 100 100 PPE (1) 100 100 PN 21 16 25 9 EP-SEBS 9 24 25 21 Mg(OH) 2 100 100 Al(OH) 3 100 100 Properties Tensile strength (Kg/cm 2 ) 250 500 240 520 Tensile elongation (%) 40 50 60 55 UL94 First firing o o o o Second firing o o o o Melt drops None None None None (Polystyrene or polyphenylene ether resin) Comparative Examples 7 8 9 10 11 12 Compounding (parts by weight) PS 100 100 100 PPE (1) 100 100 100 PN 40 80 2 EP-SEBS 40 30 2 Mg(OH) 2 100 100 100 Al(OH) 3 100 100 100 Properties Tensile strength (Kg/cm 2 ) 270 560 120 480 90 520 Tensile elongation (%) 70 50 20 58 20 35 UL94 First firing x x o x o x Second firing x x x x o x Melt drops Present Present none Present none Present Examples 9-57 and Comparative Examples 13-47 These illustrate cases wherein the component (B) and the component (C) are melt-reacted in advance. Melt reaction products A to R were obtained by using the compounding recipes shown in Tables 5-8 and by using the following methods. (1) An epoxy-modified resin (B), a halogen-free flame-retardant compound (C) (a phenol novolac resin, an amino group-containing phosphoric acid ester, a hydroxyl group-containing phosphoric acid ester or boric acid) and, if necessary, a catalyst (E) are melt-reacted using a kneader under pressure at 150°C for 30 minutes. (2) An epoxy-modified resin (B), a halogen-free flame-retardant compound (C) (a condensed phosphoric acid ester or phosphoric acid-melamine salt) and, if necessary, a catalyst (E) are melt-reacted using a kneader under pressure at 200°C for 30 minutes. The reaction between the epoxy-modified resin (B) and the halogen-free flame-retardant compound (C) was confirmed by the difference in the peak intensity of IR absorption spectrum of epoxy group before and after the reaction. (For polyolefin resins) Reaction Products A B C D Compounding (parts by weight) EP-SEBS 80 80 EP-PO 60 60 PN 20 20 40 40 TPP 0.1 0.1 PX-201 30 Boric acid 30 (For polystyrene or polyphenylene ether resins) Reaction Products E F G H Compounding (parts by weight) EP-SEBS 80 80 60 60 PN 20 20 40 40 TPP 0.1 0.1 PX-201 30 Boric acid 30 (For polyolefin resins) Reaction Products I J K L M Compounding (parts by weight) EP-SEBS 50 50 50 EP-PO 40 40 AA-1000 50 CR-757 50 50 MPP-A 60 60 PN 20 20 TPP 1 1 1 (For polystyrene or polyphenylene ether resins) Reaction Products N O P Q R Compounding (parts by weight) EP-SEBS 50 50 50 40 40 AA-1000 50 CR-757 50 50 MPP-A 60 60 PN 20 20 TPP 1 1 1 Then, the components (A) and, if necessary, the component (D) were mixed with the melt reaction product obtained above, as follows. When the component (A) was a polyolefin resin or a polystyrene resin, melt kneading was conducted by a kneader under pressure at 190°C for 30 minutes, using a compounding recipe shown in Tables 9-26. When the component (A) was a polyphenylene ether resin, melt kneading was conducted by a kneader under pressure at 300°C for 30 minutes, using a compounding recipe shown in Tables 9-26. Each of the obtained flame-retardant resin compositions was extruded into a sheet, and various test pieces were prepared from the sheet. Evaluation of various tests was made in the same manners as described above. The results are shown in Tables 9-26. (Polyolefin resins) Examples 9 10 11 12 13 14 Compounding (parts by weight) PE 100 100 EMMA 100 100 PP 100 100 Reaction product A 20 20 Reaction product B 20 20 Reaction product C 40 Reaction product D 40 Mg(OH) 2 100 100 100 Al(OH) 3 100 100 100 Properties Oxygen index 29.9 32.9 30.1 33.1 28.1 30.2 Low-temperature resistance (°C) -56 -52 -58 -50 -48 -46 Tensile strength (Kg/cm 2 ) 130 120 125 120 280 240 Tensile elongation (%) 550 520 550 500 480 460 UL94 First firing o o o o o o Second firing Δ o Δ o Δ o Melt drops None None None None None None (Polyolefin resins) Comparative Example 13 14 15 16 Compounding (parts by weight) PE 100 100 EMMA 100 100 Reaction Product A 2 Reaction product B 110 Mg(OH) 2 100 100 Al(OH) 3 100 100 Properties Oxygen index 28.0 28.2 30.9 30.9 Low-temperature resistance (°C) -58 -56 -35 -18 Tensile strength (Kg/cm 2 ) 130 135 140 100 Tensile elongation (%) 570 650 530 200 UL94 First firing x x x o Second firing x x x o Melt drops Present Present Present None (Polyolefin resin) Comparative Examples 17 18 19 Compounding (parts by weight) PP 100 100 100 Reaction Product A 2 Reaction Product B 110 Mg(OH) 2 100 100 Al(OH) 3 100 Properties Oxygen index 26.2 28.2 34.2 Low-temperature resistance (°C) -48 -46 -16 Tensile strength (Kg/cm 2 ) 280 240 190 Tensile elongation (%) 480 460 160 UL94 First firing x x o Second firing x x o Melt drops Present Present None (Polystyrene resins) Examples 15 16 17 18 Compounding (parts by weight) PS 100 100 ABS 100 100 Reaction product E 20 Reaction product F 20 Reaction product G 40 Reaction product H 40 Mg(OH) 2 80 80 Al(OH) 3 80 80 Properties Tensile strength (Kg/cm 2 ) 250 240 400 390 Tensile elongation (%) 40 35 52 50 Izod test (Kg·cm/cm) 8.8 8.4 30 29 UL94 First firing o o o o Second firing A Δ o Δ o Melt drops None None None None (Polystyrene resins) Comparative Examples 20 21 22 23 24 25 Compounding (parts by weight) PS 100 100 100 ABS 100 100 100 Reaction product E 2 Reaction product F 110 Reaction product G 2 Reaction product H 110 Al(OH) 3 80 80 80 Mg(OH) 2 80 80 80 Properties Tensile strength (Kg/cm 2 ) 260 410 250 100 460 150 Tensile elongation (%) 45 58 44 10 56 10 Izod test (Kg·cm/cm) 9.0 32 9.0 4.0 34 10 UL94 First firing x x x o x o Second firing x x x o x o Melt drops Present Present Present None Present None (Polyphenylene ether resins) Examples 19 20 21 22 Compounding (parts by weight) PPE (1) 100 100 PPE (2) 100 100 Reaction product E 50 Reaction product F 50 Reaction product G 60 Reaction product H 60 Properties Tensile strength (Kg/cm 2 ) 460 450 440 420 Heat-deformation temperature (°C) 110 108 100 98 UL94 First firing o o o o Second firing Δ o Δ o Melt drops None None None None (Polyphenylene ether resins) Comparative Examples 26 27 28 29 30 31 Compounding (parts by weight) PPE (1) 100 100 100 PPE (2) 100 100 100 Reaction product E 2 Reaction product F 110 Reaction product G 2 Reaction product H 110 Properties Tensile strength (Kg/cm 2 ) 500 500 480 200 490 120 Heat-deformation temperature (°C) 120 110 110 50 120 60 UL94 First firing x x x o x o Second firing x x x o x o Melt drops Present Present Present None Present None (Polyolefin resins) Examples 23 24 25 26 27 Compounding (parts by weight) PE 100 100 100 EMMA 100 100 Reaction product I 30 Reaction product J 30 Reaction product K 30 Reaction product L 30 Reaction product M 30 Properties Oxygen index 30.7 31.6 31.9 31.1 31.9 Low-temperature resistance (°C) -58 -60 -58 -56 -52 Tensile strength (Kg/cm 2 ) 110 105 100 115 100 Tensile elongation (%) 620 590 520 560 480 UL94 First firing o o o o o Second firing Δ Δ Δ Δ Δ Melt drops None None None None None (Polyolefin resins) Examples 28 29 30 31 32 Compounding (parts by weight) PE 100 100 100 EMMA 100 100 Reaction product I 15 Reaction product J 15 Reaction product K 15 Reaction product L 15 Reaction product M 15 Mg(OH) 2 80 80 80 80 80 Properties Oxygen index 34.6 35.2 36.4 34.8 35.2 Low-temperature resistance (°C) -58 -52 -48 -50 -46 Tensile strength (Kg/cm 2 ) 135 115 100 110 100 Tensile elongation (%) 480 500 500 480 460 UL94 First firing o o o o o Second firing o o o o o Melt drops None None None None None (Polyolefin resins) Examples 33 34 35 36 37 Compounding (parts by weight) PP 100 100 100 100 100 Reaction product I 30 Reaction product J 30 Reaction product K 30 Reaction product L 30 Reaction product M 30 Properties Oxygen index 31.7 31.6 32.2 31.4 32.1 Low-temperature resistance (°C) -60 -62 -60 -59 -59 Tensile strength (Kg/cm 2 ) 310 300 295 300 295 Tensile elongation (%) 520 490 440 520 480 UL94 First firing o o o o o Second firing Δ Δ Δ Δ Δ Melt drops None None None None None (Polyolefin resins) Examples 38 39 40 41 42 Compounding (parts by weight) PP 100 100 100 100 100 Reaction product I 15 Reaction product J 15 Reaction product K 15 Reaction product L 15 Reaction product M 15 Mg(OH) 2 80 80 80 80 80 Properties Oxygen index 35.6 36.2 36.5 35.3 36.4 Low-temperature resistance (°C) -58 -52 -50 -56 -52 Tensile strength (Kg/cm 2 ) 295 290 285 290 280 Tensile elongation (%) 480 460 480 480 440 UL94 First firing o o o o o Second firing o o o o o Melt drops None None None None None (Polyolefin resins) Comparative Examples 32 33 34 35 36 Compounding (parts by weight) PE 100 100 EMMA 100 100 100 Reaction product I 3 Reaction product J 110 Reaction product K 110 Mg(OH)2 80 80 80 80 80 Properties Oxygen index 33.0 28.8 33.4 29.8 33.4 Low-temperature resistance (°C) -48 -48 -49 -18 -15 Tensile strength (Kg/cm 2 ) 95 115 100 115 85 Tensile elongation (%) 270 450 220 500 220 UL94 First firing x x x o o Second firing x x x o o Melt drops Present Present Present none none (Polyolefin resin) Comparative Examples 37 38 39 Compounding (parts by weight) PP 100 100 100 Reaction Product I 110 Reaction Product J 3 Mg(OH) 2 80 80 80 Properties Oxygen index 28.2 38.2 28.5 Low-temperature resistance (°C) -58 -15 -52 Tensile strength (Kg/cm 2 ) 280 125 295 Tensile elongation (%) 570 250 540 UL94 First firing x o x Second firing x o x Melt drops Present None Present (Polystyrene resins) Examples 43 44 45 46 47 Compounding (parts by weight) PS 100 100 100 ABS 100 100 Reaction product N 30 Reaction product O 30 Reaction product P 30 Reaction product Q 30 Reaction product R 30 Properties Tensile strength (Kg/cm 2 ) 230 240 200 350 400 Tensile elongation (%) 30 28 20 15 20 Izod test (Kg·cm/cm) 9.0 8.8 7.8 25 30 UL94 First firing o o o o o Second firing Δ Δ Δ Δ Δ Melt drops None None None None None (Polystyrene resins) Examples 48 49 50 51 52 Compounding (parts by weight) PS 100 100 100 ABS 100 100 Reaction product N 15 Reaction product O 15 Reaction product P 15 Reaction product Q 15 Reaction product R 15 Mg(OH) 2 80 80 80 80 80 Properties Tensile strength (Kg/cm 2 ) 210 220 180 320 360 Tensile elongation (%) 20 19 16 10 15 Izod test (Kg·cm/cm) 8.6 8.2 7.2 20 26 UL94 First firing o o o o o Second firing o o o o o Melt drops None None None None None (Polystyrene resins) Comparative Examples 40 41 42 43 Compounding (parts by weight) PS 100 100 ABS 100 100 Reaction Product N 2 Reaction Product O 110 Mg(OH) 2 80 80 80 80 Properties Tensile strength (Kg/cm 2 ) 390 100 220 120 Tensile elongation (%) 15 10 30 12 Izod test (Kg·cm/cm) 28 6.0 9.2 14 UL94 First firing x x x o Second firing x x x o Melt drops Present None Present None (Polyphenylene ether resins) Examples 53 54 55 56 57 Compounding (parts by weight) PPE (1) 100 100 100 PPE (2) 100 100 Reaction Product N 15 Reaction Product O 40 Reaction Product P 15 Reaction Product Q 40 Reaction Product R 40 Properties Tensile strength (Kg/cm 2 ) 500 480 510 460 470 Heat-deformation temperature (°C) 120 110 115 110 105 UL94 First firing o o o o o Second firing Δ o Δ o o Melt drops None None None None None (Polyphenylene ether resins) Comparative Examples 44 45 46 47 Compounding (parts by weight) PPE (1) 100 100 PPE (2) 100 100 Reaction Product N 2 Reaction Product O 110 Properties Tensile strength (Kg/cm 2 ) 500 250 510 200 Heat-deformation temperature (°C) 120 60 120 50 UL94 First firing x x x o Second firing x x x o Melt drops Present Present Present None As clear from the foregoing tables, the flame-retardant resin compositions of the present invention are novel materials in which flame retardancy is significantly improved with the properties of thermoplastic resin being retained. That is, the polyolefin resin compositions of the present invention have high flame retardancy and give a molded article which causes no bleeding on the surface and which generates neither corrosive gas nor hazardous gas during processing or combustion. The polystyrene resin compositions of the present invention have flame retardancy and impact resistance and give a molded article which causes no bleeding on the surface and which generates neither corrosive gas nor hazardous gas during processing or combustion. The polyphenylene ether resin compositions of the present invention have flame retardancy and heat resistance and give a molded article which causes no bleeding on the surface and which generates neither corrosive gas nor hazardous gas during processing or combustion.

Claims: A flame-retardant resin composition obtainable by melt-kneading 100 parts by weight of (A) a thermoplastic resin and 5-100 parts by weight of a melt reaction product between (B) at least one epoxy-modified resin and (C) at least one halogen-free flame-retardant compound, said at least one epoxy-modified resin (B) being selected from the group consisting of an epoxy-modified polyolefin resin having epoxy groups in the molecule, an epoxide of a hydrogenated block copolymer obtained by hydrogenating a block copolymer comprising at least one polymer block composed mainly of a vinyl aromatic compound and at least one polymer block composed mainly of a conjugated diene compound, an epoxide of a terblock copolymer comprising a polymer block composed mainly of an acrylic resin, at least one polymer block composed mainly of a conjugated diene compound and at least one polymer block composed mainly of a vinyl aromatic compound, and an epoxide of an acrylic resin, said at least one halogen-free flame-retardant compound (C) being selected from the group consisting of a phenolic resin and phosphorus-, nitrogen- and boron-containing compounds having epoxy-reactive functional groups. A flame-retardant resin composition according to Claim 1, obtainable by melt-kneading 100 parts by weight of the thermoplastic resin (A), 5-100 parts by weight of a melt reaction product between 20-80% by weight of the epoxy-modified resin (B) and 80-20% by weight of the halogen-free flame-retardant compound (C), and 30-160 parts by weight of (D) an inorganic hydrate. A flame-retardant resin composition according to Claim 1, obtainable by melt-kneading 100 parts by weight of the thermoplastic resin (A) and 5-100 parts by weight of a melt reaction product among 20-80% by weight of the epoxy-modified resin (B), 80-20% by weight of the halogen-free flame-retardant compound (C) and 0.01-5% by weight, based on the total of (B) and (C), of (E) at least one catalyst capable of promoting the reaction between (B) and (C), selected from the group consisting of an imidazole, an amine and a derivative thereof, and an organic phosphine and a derivative thereof. A flame-retardant resin composition according to Claim 3, obtainable by melt-kneading 100 parts by weight of the thermoplastic resin (A), 5-100 parts by weight of the melt reaction product among 20-80% by weight of the epoxy-modified resin (B), 80-20% by weight of the halogen-free flame-retardant compound (C) and 0.01-5% by weight, based on the total of (B) and (C), of the catalyst (E) capable of promoting the reaction between (B) and (C), and 30-160 parts by weight of (D) an inorganic hydrate. A flame-retardant resin composition according to any one of Claims 1-4, wherein the thermoplastic resin (A) is a polyethylene, a modified polyethylene, a polypropylene, a modified polypropylene, a polystyrene resin or a polyphenylene ether resin. A flame-retardant resin composition according to any one of Claims 1-5, wherein the halogen-free flame-retardant compound (C) is a phosphoric acid ester or a polyphosphoric acid salt each having a functional group selected from the group consisting of amino group, hydroxyl group and carboxyl group. A flame-retardant resin composition according to any one of Claims 1-5, wherein the halogen-free flame-retardant compound (C) is boric acid or zinc borate. A flame-retardant resin composition according to any one of Claims 1-5, wherein the halogen-free flame-retardant compound (C) is at least one compound selected from the group consisting of melamine, a melamine derivative, guanidine and a guanidine derivative. A flame-retardant resin composition according to any one of Claims 1-8, wherein the inorganic hydrate (D) is magnesium hydroxide, aluminum hydroxide or calcium hydroxide. Shaped articles comprising a flame-retardant resin composition according to any one of Claims 1 to 9.

Inventors: TERAO MASARU, YANAGISAWA KENICHI, TERAO, MASARU, YANAGISAWA, KENICHI
Applicants: SUMITOMO BAKELITE CO, SUMITOMO BAKELITE COMPANY LIMITED
Application year: 1994
Main classification: C08L101
IPC codes: C08K5, C08G59, C08L63, C08L101